KR20220033733A - Engine system including divided exhaust system - Google Patents

Abstract

Disclosed is an engine system including a separate exhaust system. The engine system including the separate exhaust system according to an embodiment of the present invention may comprise the separate exhaust system including: an engine including a plurality of combustion chambers for generating a power by combustion of a fuel; an intake passage through which an intake air supplied to the combustion chamber flows; a separate exhaust system including a plurality of exhaust passages so that an exhaust gas discharged from the combustion chamber is discharged with a predetermined time difference; and an electric turbocharger comprising a turbine provided in one of the exhaust passages among the plurality of exhaust passages, a compressor provided in the intake passage and rotating in conjunction with the compressor, and an electric motor assisting a rotary force of the compressor. An objective of the present invention is to provide the engine system including the separate exhaust system capable of widening a regenerative power generation area of the electric turbocharger.

Description

Engine system with separate exhaust system {ENGINE SYSTEM INCLUDING DIVIDED EXHAUST SYSTEM}

The present invention relates to an engine system including a separate exhaust system, and more particularly, to an engine system including a separate exhaust system capable of increasing the amount of regenerative braking of an electric turbocharger.

In the process of generating power by driving the engine, the desired output and combustion efficiency can be obtained only when sufficient external air is supplied for combustion. To this end, a turbocharger is used as a device for supercharging combustion air in order to increase the combustion efficiency of the engine.

In general, a turbocharger is a device for increasing the output of an engine by supplying high-pressure air to a combustion chamber using the rotational force of a compressor rotating in conjunction with the turbine after rotating a turbine using the pressure of exhaust gas discharged from the engine.

The turbocharger is applied to most diesel engines, and recently it is also applied to gasoline engines.

Since the conventional turbocharger operates by exhaust gas, a problem of poor responsiveness has occurred. In order to solve this problem, an electric turbocharger having a motor for assisting the rotational force of a compressor of a conventional turbocharger has been developed.

Since the operation area in which the motor of the electric turbocharger is used is limited, in the operation area in which the motor is not used, it is necessary to regenerate exhaust energy through the motor.

However, when regenerative power is generated through the motor provided in the electric turbocharger, the pressure of the upstream (or front end) of the turbine is increased. Accordingly, there is a problem in that the combustion efficiency is lowered because the pumping loss increases and the ignition timing must be delayed.

That is, it is very rare that the regenerative energy generated by the motor of the electric turbocharger is greater than the pumping loss and the reduction in combustion efficiency, making it difficult to generate regenerative power through the electric turbocharger.

Matters described in this background section are prepared to promote understanding of the background of the invention, and may include matters not already known to those of ordinary skill in the art to which this technology belongs.

An object of the present invention is to solve the above problems, and an object of the present invention is to provide an engine system including a separate exhaust system capable of expanding a regenerative power generation area of an electric turbocharger.

An engine system including a separate exhaust system according to an embodiment of the present invention for achieving the above object includes an engine including a plurality of combustion chambers for generating power by combustion of fuel; an intake passage through which intake air supplied to the combustion chamber flows; a separate exhaust system including a plurality of exhaust passages so that the exhaust gas discharged from the combustion chamber is discharged with a predetermined time difference; A turbine provided in any one of the exhaust passages among the plurality of exhaust passages, a compressor provided in the intake passage and rotating in conjunction with the compressor, and an electric turbocharger including an electric motor assisting the rotational force of the compressor; A separate exhaust system may be included.

The separated exhaust system may include: a blow-down passage connected to one of a pair of exhaust valves provided in the combustion chamber; a blow-down valve installed in the blow-down flow path; a scavenging flow path connected to the other exhaust valve among a pair of exhaust valves provided in the combustion chamber; and a scavenging valve installed in the scavenging flow path.

An opening/closing timing of the blow-down valve may be earlier than an opening/closing timing of the scavenging valve.

In an engine system including a separate exhaust system according to an embodiment of the present invention, a recirculation passage branching from the blowdown passage and joining the intake passage, a recirculation cooler installed in the recirculation passage, and a recirculation valve installed in the recirculation passage It may further include; an exhaust gas recirculation device comprising a.

The recirculation passage may branch downstream of the blow-down valve installed in the blow-down passage.

The electric motor may operate as a generator in a medium-speed and heavy-load region to generate a rotational force of the turbine rotated by exhaust gas as electrical energy.

The turbine of the electric turbocharger may be installed in the blowdown flow path downstream of the blowdown valve.

The blow-down flow path and the scavenging flow path may merge into a main exhaust flow path, and a catalytic converter may be provided in the main exhaust flow path.

An engine system including a separate exhaust system according to an embodiment of the present invention includes: a bypass passage branching from the blowdown passage upstream of the turbine and joining into the main exhaust passage downstream of the turbine; and a bypass valve provided in the bypass passage.

According to the engine system including the separated exhaust system according to the embodiment of the present invention as described above, by providing the electric turbocharger in the separated exhaust system, regenerative power generation is performed through the electric motor of the electric turbocharger in a wide operating area. can

These drawings are for reference in describing an exemplary embodiment of the present invention, and the technical spirit of the present invention should not be construed as being limited to the accompanying drawings.
1 is a conceptual diagram illustrating a configuration of an engine system including a separate exhaust system according to an embodiment of the present invention.
2 is a PV diagram for explaining regenerative power generation by an electric turbocharger of an engine system including a separated exhaust system according to an embodiment of the present invention.
3 is a graph illustrating an operating region of an engine system including a separate exhaust system according to an embodiment of the present invention.

With reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be implemented in several different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of explanation, the present invention is not necessarily limited to the bar shown in the drawings, and the thickness is enlarged to clearly express various parts and regions. it was

As used herein, "vehicle", "car", "vehicle", "automobile" or other similar terms refers to sports utility vehicles (SUVs), buses, trucks, passenger vehicles, including various commercial vehicles, and various types of vehicles. including automobiles, including boats and ships, aircraft and the like of fuel) including vehicles.

Hereinafter, an engine system including a separate exhaust system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram illustrating the configuration of an engine system including a separate exhaust system according to an embodiment of the present invention.

As shown in FIG. 1 , an engine system including a separate exhaust system according to an embodiment of the present invention includes an engine 10 , a separate exhaust system 30 , an electric turbocharger 60 , and an exhaust gas recirculation device 70 . ) may be included.

It includes a plurality of combustion chambers 11 that generate power required for driving of the vehicle by combustion of fuel in the engine, and the intake air passage 20 through which intake air supplied to the engine flows may be connected through the intake manifold 22 . . The intake manifold 22 is provided with a throttle valve 24 , so that the flow rate of intake air supplied to the intake manifold can be adjusted by the opening amount of the throttle valve 24 .

A pair of intake valves 13 are provided in the combustion chamber 11 , and intake air introduced through the intake manifold 22 by opening and closing the intake valve 13 may be introduced into or blocked from the combustion chamber 11 .

A pair of exhaust valves 15 are provided in the combustion chamber 11 , and exhaust gas discharged through the exhaust system 30 separated by opening and closing of the exhaust valve 15 may be discharged or blocked. In an embodiment of the present invention, the pair of exhaust valves 15 may include a first exhaust valve 15 and a second exhaust valve 15 .

The separated exhaust system 30 includes a blowdown exhaust manifold 40 connected to the first exhaust valve 15 of the pair of exhaust valves 15 , and a scavenging exhaust connected to the second exhaust valve 15 . A manifold 50 may be included.

The blowdown exhaust manifold 40 is connected (or communicated with) the blowdown exhaust flow path 41 , and the blowdown exhaust manifold 40 or the blowdown exhaust flow path 41 is provided with a blowdown valve 43 . can be

The scavenging exhaust manifold 50 may be connected (or communicated with) the scavenging exhaust flow path 51 , and a scavenging valve 53 may be provided in the scavenging exhaust flow path 51 .

The blow-down exhaust flow path 41 and the scavenging exhaust flow path 51 join into the main exhaust flow path 31 , and the catalytic converter 33 may be provided in the main exhaust flow path 31 . The catalytic converter 33 may include a warming-up catalytic converter (WCC) and an under-floor catalytic converter (UCC) catalyst at the bottom of the vehicle.

The blow-down valve 43 and the scavenging valve 53 may be opened and closed with a predetermined time difference. In an embodiment of the present invention, the blow-down valve 43 may open and close earlier than the scavenging valve 53 , and the scavenging valve 53 may open and close later than the blow-down valve 43 .

The electric turbocharger 60 is provided in the turbine 61 provided in the blow exhaust passage, the compressor 63 provided in the intake passage 20 and rotated in conjunction with the turbine 61, and the compressor 63 assisting the rotational force It may include an electric motor 65 . The compressor 63 may compress the intake air flowing through the intake air passage 20 and supply it to the combustion chamber 11 .

The electric motor 65 may selectively operate as a generator to generate the rotational force of the turbine 61 as electrical energy and store it in a battery. In an embodiment of the present invention, the electric motor 65 may operate as a generator to generate electrical energy using the rotational force of the turbine 61 when the engine operation region is a medium-speed and heavy-load region.

An intercooler 26 is provided in the intake flow path 20 downstream of the compressor 63, and the high-temperature and high-pressure compressed air compressed by the compressor 63 is cooled by the intercooler 26 to the combustion chamber 11 of the engine. can be supplied.

The exhaust gas recirculation apparatus 70 (EGR apparatus: exhaust gas recirculation apparatus) re-supply a part of the exhaust gas discharged from the combustion chamber 11 of the engine to the combustion chamber 11 to reduce the amount of oxygen contained in the intake air and prevent combustion. Suppresses the generation of nitrogen oxides. To this end, the exhaust gas recirculation device 70 may include a recirculation passage 71 , a recirculation valve 73 , and a recirculation cooler 75 .

The recirculation flow path 71 may branch from the blowdown flow path downstream of the blowdown valve 43 and merge into the intake flow path 20 . A recirculation valve 73 for controlling the amount of recirculation gas may be provided in the recirculation passage 71 . In addition, a recirculation cooler 75 may be provided in the recirculation passage 71 to cool the recirculated exhaust gas.

On the other hand, in the engine system including the separated exhaust system according to the embodiment of the present invention, a bypass flow path that branches from a blowdown flow path upstream of a turbine and merges into a main exhaust flow path downstream of a turbine, and a bypass valve provided in the bypass flow path may further include. The amount of exhaust gas supplied to the turbine of the electric turbocharger can be controlled through the bypass valve.

Hereinafter, the operation of the engine system including the separated exhaust system according to the embodiment of the present invention as described above will be described.

3 is a graph illustrating an operating region of an engine system including a separate exhaust system according to an embodiment of the present invention.

Referring to FIG. 3 , since high engine output is required in a high load region, a large boost pressure must be generated through the electric turbocharger 60 . That is, all of the exhaust energy by the exhaust gas discharged to the combustion chamber 11 of the engine is supplied to the turbine 61 and a boost pressure must be generated through the compressor 63 . If necessary, since the rotational force of the compressor 63 must be assisted through the electric motor 65 , regenerative power generation through the electric motor 65 of the electric turbocharger 60 is not performed.

Regenerative power generation is achieved by the electric turbocharger 60 in the medium speed and heavy load region. That is, when the rotational force of the turbine 61 is converted into electrical energy by the electric motor 65 of the electric turbocharger 60 , in the region where the blow-down valve 43 is opened, the front end of the turbine 61 (or upstream ) increases the back pressure. However, when the scavenging valve 53 is opened, the back pressure of the rear end (or downstream) of the turbine 61 is reduced, and the back pressure of the front end of the turbine 61 is also reduced. That is, the overall exhaust system back pressure is reduced and the pumping loss is reduced.

Therefore, even if the rotational force of the turbine 61 is regeneratively generated through the electric motor 65 of the electric turbocharger 60, the pumping loss is minimized and there is no need to delay the ignition timing. Regenerative power generation may be performed through the motor 65 .

In the medium speed and heavy load region, a pumping loss may occur in which the target boost pressure is not relatively high and the exhaust pressure is high compared to the boost pressure. However, since the back pressure of the rear end of the turbine 61 is reduced by the opening of the scavenging valve 53 , regenerative power generation by the electric motor 65 of the electric turbocharger 60 is possible.

Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and it is possible to carry out various modifications within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and this also It goes without saying that it falls within the scope of the invention.

10: engine
11: combustion chamber
13: intake valve
15: exhaust valve
20: intake flow path
22: intake manifold
30: separated exhaust system
31: main exhaust flow path
33: catalytic converter
40: blow down exhaust manifold
41: blow-down exhaust flow path
43: blow down valve
50: scavenging exhaust manifold
51: scavenging exhaust flow path
53: scavenging valve
60: electric turbocharger
61: turbine
63: compressor
65: electric motor
70: exhaust gas recirculation device
71: recirculation flow path
73: recirculation valve
75: recirculation cooler

Claims (9)

an engine including a plurality of combustion chambers for generating power by combustion of fuel;
an intake passage through which intake air supplied to the combustion chamber flows;
a separate exhaust system including a plurality of exhaust passages so that the exhaust gas discharged from the combustion chamber is discharged with a predetermined time difference;
an electric turbocharger including a turbine provided in one of the exhaust passages among the plurality of exhaust passages, a compressor provided in the intake passage and rotating in conjunction with the compressor, and an electric motor assisting the rotational force of the compressor;
An engine system comprising a separate exhaust system comprising: According to claim 1,
The separated exhaust system
a blow-down passage connected to any one of a pair of exhaust valves provided in the combustion chamber;
a blow-down valve installed in the blow-down flow path;
a scavenging flow path connected to the other exhaust valve among a pair of exhaust valves provided in the combustion chamber;
a scavenging valve installed in the scavenging flow path;
An engine system comprising a separate exhaust system comprising: 3. The method of claim 2,
and an opening/closing timing of the blow-down valve is earlier than an opening/closing timing of the scavenging valve. 3. The method of claim 2,
a recirculation passage branching from the blow-down passage and joining the intake passage;
A recirculation cooler installed in the recirculation passage, and
A recirculation valve installed in the recirculation passage,
Exhaust gas recirculation device comprising;
An engine system comprising a separate exhaust system further comprising a. 5. The method of claim 4,
and the recirculation passage includes a separate exhaust system branching downstream of the blow-down valve installed in the blow-down passage. According to claim 1,
The electric motor is
An engine system comprising a separate exhaust system that operates as a generator in a medium-speed and heavy-duty region to generate electrical energy by generating rotational force of the turbine rotated by exhaust gas. 3. The method of claim 2,
The turbine of the electric turbocharger includes a separate exhaust system installed in the blowdown flow path downstream of the blowdown valve. 3. The method of claim 2,
The blow-down flow path and the scavenging flow path join as a main exhaust flow path,
and a separate exhaust system provided with a catalytic converter in the main exhaust passage. 9. The method of claim 8,
a bypass passage branching from the blowdown passage upstream of the turbine and joining the main exhaust passage downstream of the turbine; and
a bypass valve provided in the bypass passage;
An engine system comprising an exhaust system further comprising a.

Images